Two notes can make an empty stretch of water feel dangerous. Before a fin breaks the surface, before anyone screams, the music in Jaws has already suggested what might be underneath. You are watching the ocean, but listening for a shark.
Horror movie music can scare us by shaping what we expect and giving an unseen threat a recognisable sound. Harsh textures can also make music feel more emotionally intense. The effect comes from the sound itself, its timing and the story we attach to it.
John Williams understood how much a small musical idea could carry. In a BBC programme, he recalled demonstrating his Jaws idea to Steven Spielberg at the piano: two low notes, eventually joined by a third. Spielberg questioned whether something so simple would work. Williams explained that cellos and basses would give it the threatening character he wanted.
The result is an example of music doing narrative work. As Williams biographer Tim Greiving explains, the theme can stand in for a shark the audience cannot see, with changes in speed helping convey its proximity. The repetition gives the danger continuity. Something seems to remain present beneath the picture, even when the picture offers little to confirm it.
Psycho offers a different experience. Bernard Herrmann’s score uses sharply clashing strings, which the Library of Congress highlights in its description of the film. In the shower sequence, their repeated attacks make the music feel almost physical. Listen to the texture: the strings seem to shriek, cutting into the scene instead of settling into a comfortable accompaniment.
Those two examples invite different listening questions. In Jaws, when does the pattern begin, and how does it change your attention? In Psycho, what happens at the instant the strings arrive? A score can create dread through persistence, or make a moment feel brutally immediate through the character of its sound.
Researchers have investigated whether some of these disturbing qualities resemble sounds associated with distress. In a 2010 study, Daniel Blumstein and colleagues analysed short extracts from 102 films across four genres. They found genre-specific differences in acoustic features, including more noisy screams than expected in horror. Their analysis covered whole soundtracks, including voices and effects, so it did not isolate the emotional impact of the music alone.
The researchers’ hypothesis connects film sound to animal vocalisations. Under stress, vocal systems can produce harsh, irregular sounds. Composers and sound designers can create comparable qualities using instruments or electronic processing. The suggestion is that some unsettling soundtrack textures draw on sensitivities that also help us notice distress. This is a proposed explanation, rather than proof that every frightening score works the same way.
A 2012 follow-up moved from analysing films to testing listeners. The team created short musical excerpts and versions containing added noise or sudden pitch shifts. In the music-only experiment, involving 42 university students, these alterations changed ratings of how emotionally stimulating the pieces were and how positive or negative they felt. The measurements concerned emotional judgements; they were not a direct measure of how terrified someone would become during a film.
Context changed the result. In a second experiment, the researchers paired the music with ordinary, non-threatening videos. The sound alterations no longer produced the same differences in arousal, although some differences in positive or negative emotional ratings remained. The visual information affected how the music was experienced.
For a filmmaker, that is a useful reminder to listen with the scene in front of you. A sound that feels menacing in isolation may do something different beside a face, a landscape or a joke. The audience is interpreting an event, with the music helping to suggest what that event means.
You can explore this with a familiar suspense scene. Watch it once normally, then once muted. Notice which moments still feel threatening and which lose their urgency. Afterwards, listen without watching. Pay attention to repetition, changes in pace, the arrival of a new sound and the spaces between phrases. This informal comparison reveals how much you had been taking the soundtrack for granted.
The most revealing moment may come before anything happens on screen. A character has stopped moving. The room looks empty. Yet you find yourself watching the doorway more carefully. Somewhere in the soundtrack, the film has given you a reason to expect trouble.